In my opinion ,it is best to have no experience before u start JKD, as from bruce's Tao of JKD he states that you should forget all martial art techniques becuase JKD has no style or form, but on the contrary he states that JKD can fit in with all styles. But when i began training my instructers asked me if i had any martial art background, which i had not, only absorbing bruces art and ideas from the TAO. But they did much prefer it that i had no experience so i wouldnt have to forget any other styles.
They also said it wouldnt hurt to have sum TKD Kicking training.

So maybe one day if you would happen to see Kareem Abdul Jahbar on the street, you could give him a good pop to the head. ^_^
Hope i gave you some help, and good luck to you in your JKD training, it is a very good lifestyle to lead.